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111.
The header stack-barge was a device that farmers on the American and Canadian plains invented to adapt wheat harvesting machinery to the special requirements of their semi-arid region. Although it appeared at points scattered throughout the length of the North American plains, its greatest use was in Alberta and Saskatchewan during the 1930s. The development of the header stack-barge was an outstanding example of folk technology in the agricultural history of the Great Plains, showing the conditions under which folk invention might flourish and the way it might interact with government extension agents. The case of the header stack-barge then is of consequence both to folklore and to concepts of Great Plains regionalism. 相似文献
112.
Kevin J. A. Thomas 《Demography》2009,46(3):513-534
In this study, I examine disparities in schooling progress among children born to immigrant and U.S.-born blacks. I find that
in one- and two-parent families, children born to black immigrants are less likely to fall behind in school than those born
to U.S.-born blacks. In two-parent immigrant families, children born to two immigrant parents have a significant schooling
advantage over children born to one immigrant parent. While children born to two immigrant parents in the wealthiest black
immigrant families do better in the second generation than in the first, the reverse is observed among children in less wealthy
families. These findings contribute in two ways to our understanding of the assimilation processes of children born to black
immigrant parents. First, they show that there is a positive association between the number of immigrant parents in a family
and children’s schooling performance. Second, they suggest that disparities in the assimilation patterns of the children of
black immigrants are a likely product of the interaction between their parental characteristics and the socioeconomic circumstances
of their families. 相似文献
113.
114.
The study explores and distinguishes links between parental status (childless persons, parents with residential children,
and empty nest parents) and a range of psychological well-being outcomes in midlife and old age. Data are from the first wave
of the Norwegian Life Course, Ageing and Generation (NorLAG) study (n = 5,189). We separate outcomes into cognitive (life satisfaction and self-esteem) and affective (positive and negative affect,
depression, loneliness) components. Parental status has a net effect on cognitive well-being among women, as childless women
report significantly lower life satisfaction and self-esteem than both mothers with residential children and empty nest mothers.
However, motherhood is inconsequential for affective well-being. Among men, parental status is unrelated to any of the well-being
aspects. Parental status effects are not modified by age, marital status, and education. The results demonstrate the importance
of investigating the effect of parental status and other objective circumstances on a range of psychological well-being outcomes.
Furthermore, the results reviewed and presented indicate somewhat more positive effects of parenthood in the Nordic countries
than in the US, highlighting the role of social policies in shaping the impact of parental status on well-being. 相似文献
115.
For regression on state and transition probabilities in multi-state models Andersen et al. (Biometrika 90:15–27, 2003) propose
a technique based on jackknife pseudo-values. In this article we analyze the pseudo-values suggested for competing risks models
and prove some conjectures regarding their asymptotics (Klein and Andersen, Biometrics 61:223–229, 2005). The key is a second
order von Mises expansion of the Aalen-Johansen estimator which yields an appropriate representation of the pseudo-values.
The method is illustrated with data from a clinical study on total joint replacement. In the application we consider for comparison
the estimates obtained with the Fine and Gray approach (J Am Stat Assoc 94:496–509, 1999) and also time-dependent solutions
of pseudo-value regression equations. 相似文献
116.
This paper considers estimation and prediction in the Aalen additive hazards model in the case where the covariate vector
is high-dimensional such as gene expression measurements. Some form of dimension reduction of the covariate space is needed
to obtain useful statistical analyses. We study the partial least squares regression method. It turns out that it is naturally
adapted to this setting via the so-called Krylov sequence. The resulting PLS estimator is shown to be consistent provided
that the number of terms included is taken to be equal to the number of relevant components in the regression model. A standard
PLS algorithm can also be constructed, but it turns out that the resulting predictor can only be related to the original covariates
via time-dependent coefficients. The methods are applied to a breast cancer data set with gene expression recordings and to
the well known primary biliary cirrhosis clinical data. 相似文献
117.
Liu CA Braun TM 《Journal of the Royal Statistical Society. Series C, Applied statistics》2009,58(2):225-236
We propose a phase I clinical trial design that seeks to determine the cumulative safety of a series of administrations of a fixed dose of an investigational agent. In contrast with traditional phase I trials that are designed solely to find the maximum tolerated dose of the agent, our design instead identifies a maximum tolerated schedule that includes a maximum tolerated dose as well as a vector of recommended administration times. Our model is based on a non-mixture cure model that constrains the probability of dose limiting toxicity for all patients to increase monotonically with both dose and the number of administrations received. We assume a specific parametric hazard function for each administration and compute the total hazard of dose limiting toxicity for a schedule as a sum of individual administration hazards. Throughout a variety of settings motivated by an actual study in allogeneic bone marrow transplant recipients, we demonstrate that our approach has excellent operating characteristics and performs as well as the only other currently published design for schedule finding studies. We also present arguments for the preference of our non-mixture cure model over the existing model. 相似文献
118.
John Ermisch Diego Gambetta Heather Laurie Thomas Siedler S. C. Noah Uhrig 《Journal of the Royal Statistical Society. Series A, (Statistics in Society)》2009,172(4):749-769
Summary. We measure trust and trustworthiness in British society with a newly designed experiment using real monetary rewards and a sample of the British population. The study also asks the typical survey question that aims to measure trust, showing that it does not predict 'trust' as measured in the experiment. Overall, about 40% of people were willing to trust a stranger in our experiment, and their trust was rewarded half of the time. Analysis of variation in the trust behaviour in our survey suggests that trusting is more likely if people are older, their financial situation is either 'comfortable' or 'difficult' compared with 'doing alright' or 'just getting by', they are a homeowner or they are divorced, separated or never married compared with those who are married or cohabiting. Trustworthiness also is more likely among subjects who are divorced or separated relative to those who are married or cohabiting, and less likely among subjects who perceive their financial situation as 'just getting by' or 'difficult'. We also analyse the effect of attitudes towards risks on trust. 相似文献
119.
Scheike TH 《Lifetime data analysis》2006,12(4):461-480
I suggest an extension of the semiparametric transformation model that specifies a time-varying regression structure for the
transformation, and thus allows time-varying structure in the data. Special cases include a stratified version of the usual
semiparametric transformation model. The model can be thought of as specifying a first order Taylor expansion of a completely
flexible baseline. Large sample properties are derived and estimators of the asymptotic variances of the regression coefficients
are given. The method is illustrated by a worked example and a small simulation study. A goodness of fit procedure for testing
if the regression effects lead to a satisfactory fit is also suggested. 相似文献
120.
There are obvious reasons why residential construction should depend on the population’s age structure. We estimate this relation
on Swedish time series data and Organization for Economic Cooperation and Development panel data. Large groups of young adults
are associated with higher rates of residential construction, but there is also a significant negative effect from those above
75. Age effects on residential investment are robust and forecast well out-of-sample in contrast to the corresponding house
price results. This may explain why the debate around house prices and demography has been rather inconclusive. Rapidly aging
populations in the industrialized world makes the future look bleak for the construction industry.
相似文献
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